Polyethylene gravimetric analysis

J. Schirmer, J. S. Kim and E. Klemm, Catalytic degradation of polyethylene using thermal gravimetric analysis and a cycled-spheres-reactor, Journal of Analytical and Applied Pyrolysis, 60, 205-217 (2001). 

Polyethylene and polypropylene are especially interesting as additives for the activation of the cracking reaction of vacuum residue. The data obtained from thermo-gravimetric analysis of polyethylene and polypropylene show that vacuum residue has its maximum cracking velocity at the temperature 456°C, polypropylene at 450°C and polyethylene at 485°C. This means that the cracking of vacuum residue will only be activated if polypropylene is used. In the case of the thermal treatment of vacuum residue and polyethylene mixtures, the cracking of polyethylene will be activated by free radicals from the vacuum residue (see above). 

Corrales, T., Catalina, F., Peinado, C., Allen, N.S., Fontan, E. Photooxidative and thermal degradation of polyethylenes interrelationship by chemiluminescence, thermal gravimetric analysis and FTIR data. J. Photochem. PhotobioL, A 147, 213-224 (2002)... 

For classes (a)-(c) and for SiC, the main analysis solution is prepared via a low flux/sample ratio fusion or, in the case of alumina, a sinter at 1200°C. The flux used is a mixture of fusion mixture (NaKCOs) and boric acid a lower flux/sample ratio is used for aluminous materials, and a larger flux/ sample ratio is used for zircons. The melt is dissolved and the silica is dehydrated in a mixture of hydrochloric and sulfuric acids with the assistance of polyethylene oxide. The main silica is then determined gravimetrically. Other constituents, including residual silica, are determined on the filtrate combined with the residue remaining after the gravimetric silica determination. 

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